Telephone-receiver.



A. ROSENBERG.

TELEPHONE RECEIVER.

APPLIOATION FILED 11111.24. 1912.

Patented May 12, 1914.

2 SHEETS-SHEET l.

//v VEN rol? BV A Arm/PA/EJG A. ROSENBERG. TELEPHONE RECEIVER.

APPLICATION H LED JAN.24,1912.

Patented May 12, 1914.

2 SHEETS-SHEET 2.

lUNITED fsTATEs PATENT oEEioE.

AUGUSTUS v ROSIENIBERG, OF LONDON, ENGLAND. v

TELEPHONE-RECEIVER.

Specification of Letters Patent.

To all :whom t may concern: i n Be 1t lmwn that I, AUGUSTUS ROSENBERG,

a subject of the King-ofl Great Britain, and

resident of 259 High Hol-born, London, W. C., England,lengineer, have invented certain new and useful Improvements in Telephone-Receivers, of which the following is a specification.

This invention relates to watch-form telephone receivers of the electro-magnetic po larized type moreespecially designed for the use of persons of imperfect hearing, and

has for its object on the one hand to pro.-

vide a receiver whose sound-magn'ifyingl` powers may, with the greatest convenience,l

be varied by each individual to suit his requirements between limits very much reater than those of'siniilar apparatus as eretofore constructed, and on the other Vhand to `reduce to a minimum the dimensions,

weight, and cost of the apparatus.

.For the purpose of the invention, movement ofl the magnetic pole-piece or polepieces toward andfr'om the vibratory diaphragm is permitted with a. view to enablin the width of the vair gap to bevaried at wil -and according to the present invention the means employed for producing such movement consist in the combination of a spring tending to move the pole-piece or pole-pieces in one direction or the other, a manually 'rotatable member carrying a vpointer movable over a scale onthe outside of the casing, and screw-mechanism operableby said member for transmitting to the pole-piece or pole-pieces movement 1n a direction contrary to that produced by the spring.

The invention will be described with reference to the accompanying drawings wherein Figure 1 is a vertical section and Fig. 2 a face view with the cover removed showing a typical form of receiver wherein the casing is of conductive material and whereinthe core of the receiver coil is alone adjustable;

relatively to the diaphragm. Figs. 3 and4 are similar views correspondin 'respecftivel to Figs. 1 and 2, wherein t e casing is o permanently magnetized. metal and? e constitutes the body of the permanent magi" net. Figs. 5 and 6 are similar views corresponding respectively to Figs. 1M and 2, wherein the receiver coil core is rigidly mounted on the permanent magnet and wherein the core and the `magnety areadjustable as a whole relatively to the diaphragm. Fig. 7 is a rear elevation of the responding parts throughout the drawings.

The polarized magnetic receiver is either provided with a magnet whose body-portion is of permanently magnetized metal as Patented May 12, 1914.'4 applicati@ mea January 24, 1912. serial No. 673,222.

shown in Figs. l and 2 and 5 and 6, or the casing of the receiver maybe of permanently niagnetized metal, as shown in Figs. 3 and 4. The Casin of the receiver consists of two parts, name y a foundation-disk K forming the back of the casing) which has a substantially'cylindrical marginal flange la, and a covering disk L having a similar phragm M'is clampedl between the edge of the liange lc and a peripheral corrugation or beading, such as indicated atll, encircling the margin of the covering disk L, whose main or central portion is thus odset-from the diaphragm M so as to adord the latter anple space and freedom to vibratewhile the covering disk has a central'aperture Z2 (or a number of perforations) to permit of the aerial sound-waves set up by the lvibra'- tion of the diaphragm M to reach the ear of the user.

. In cases Where (as in Figs.` 3 and 4) vthe foundation-disk K is of magnetizable met-al l magnet, while the other pole-piece is coiistituted` by a permanently magnetized stud N carrying (or passing through) the electro-magnetic winding O` and so mounted concentrically with the disk -K as to be ad- 4justable toward and from thev dia hragmM for the purpose of varying the width of the ypolar kair-gap w.

In cases where (as in Figs. 1 and 2) the foundation-disk K is of non-magnetic'material, the magnet, which is then inclosed within the casing, may be of any convenient character or construction provided that at least one of its pole-pieces is capable of adjustment toward and from the central poran'ge Z which lits over and-is secured to the.'l flange in any suitable manner. The dia-h tion of the diaphragm M. In the example y ufrom the diaphragm varying L adjustment of the 2 the body of the magnet is constituted b tending diametrically o the casing and hav`- v ing its ends p forwardll7 bent so as to approach the diaphragm pole of opposit manently magldetized iron stud N carrying (or passing t rough) the bar P and wind- 1n thi disk K as to be adjustable toward and M for the purpose of the width of the pflar air-gap fw. In the example illustrated'in Figs. 5 and 6 the body of the magnet is'constituted by an iron bar 2 each of whose 'extremities passes through the flange )t of the casing as at 3, 4. The casing K should preferably be of non-magnetizable material while the core L and ange Z, the latter of which is in contact with the outer pole pieces of the magnet 2, should be of'magnetizable material so as" to complete the magnetic circuit. The pole-piece- N is, in-all cases, eilt'ected bymeans of a nut Q screwing on the threaded outer end ln, of the stud N :lvhliph passes through an aperture in the 1s rearward in opposition to the stress of a spring R, which is shown in Fig. 3 as interposed betweene the disk K and a shoulder on the stud, in Fig. 1 as interposed between the magnet-bar P and the coil, and in Fig. 5 as interposed between the disk K and the magnet 2. In all cases the receiver coil moves as one withthe stud it is intended to Aarc e V(Fig. 7)

magnetize., as prevented from rotating along with' the nut Q b. being provided with a square or D-shape portion (Fig. 1) which engages in a correspondingly shaped -hole in the bar P (the latter being held against rotation by bolts or screws p1), and in Fig. 3 engages in a correspondingly shaped hole in the spring R'which in turn is disk K by means of bolts or screws p1. The nut Q carries a pointer T which moves (with the rotation ofthe nut) over a'scale-markedv on the 'outer face of the dis K so as to enable a suitable adjustment of the width of the polar air-gap w,when once determined, to be readily recovered after accidental disturbance. The ready adj ustability of the air-gap lw also renders it possible for receivers of identical construction to be made to serve for users havingwidely dif- -erent requirements, so that the expense attendant upon making receivers to suit the special requirements of particular users may be entirely (or almost entirely) obviated.

It will be observed that in the forms of receiver illustrated, the magnetic circuit 1s' these ends p both` constituting poles of the same sign while the sign is constituted by a per- V(for example) 4 a switch S is provided within theA casingof O and so lmounted concentrically withl externally-presented K, the nut Q'serving to draw-the stud In each case the stud N is shown` held on to the foundation# tocara? 'l rendered very'v sensitive. In the example illustrated in Fig. 3, wherein the foundationdisk K is understood to form the body of the magnet, this result `is `independent of whether the cover L is of magnetizable materialor not. v

In order to `obviatevvaste of current when the apparatusis not in use,

the receiver, whereby to enable the electric circuit to be broken. at will. Thisswitch consists 'of a :spring blade pivoted to the foundation-disk K as at s and lprovided with a handle constituted (for example) by the head of the pivot-pin One end of the winding O of the elec- .tro-magnet is in each case shown as connected to Ia terminal u which is'flxed to the foundation-disk Kin position to .establish contact with the switch S when the latter is in the operative position (the inoperative or open position being shown in Fig. 2). The opposite end of the winding-0I is connected to one of the memberspof the iiexible conductor, both- -of 'Whose Ime'r'nbers are led through the wall of the casing of the receiver, preferably at orl near its lower side, as indicated. The other member of the conductor is connected to the ivot s of switch S through the medium of t e disk K where,

as in Fig. 4, this disk is of metal.- In the latter case theterminal u would, of course, require to beinsulated from the disk K.

The receiver may be providedat'its upper extremity withan extension v13 adapted to be secured to a band (not shown) placed around Y the users head and serving to-hold the receiver` in position over the ear or earsof the'aiicted person, thus allowing them the full use of their hands when using the apparatus.

In the drawings each receiver is provided with a `single movable stud N and coil. If desired, more than'one stud and coil may be employed, in which case the nut Q would be secured to the stems n of one of the studs N and means (i. e. gearing) would be provided or .concurrently varying to an equal amount the air-gap between each stud and the diaphragm.

As will be seen in Figs. 2, 4 and 6, the incoming wires 4may conveniently be held within the casing by means of a clamp 14 secured to the casing by means of one of the bolts p1.

It will be observed that all the elements comprised -in the apparatus 'are of the simplest character and construction, and that the foundation and covering disks constitut-` ing the casing of the receiver, whether formed' of metal or of.nonconductive material, may be stampings., castings, or I with the minimum of skilled labor and hence the cost of production is exceedingly small.

Claims.

l. In a telephone receiver of the watch type the combination with a casing of a magnet having radially disposed poles a central pole-piece provided with a shoulder at its lower end, a shank extending therefromv through said casing, the end of said shank being threaded, a spring under compression between said shoulder and the casing, means interacting between the spring and said shank to prevent the latter and its pole-piece from turning, a nut on the threaded end of said shank provided with a pointer anda graduated scale on the back of said receiver casing with which said pointer is adapted to coperate.

2. In a telephone receiver 'of the watch type the combination with a casing composed of telescoping members of a magnet having radially disposed poles, said poles disposed magnet and through the back of said casing, the end of the shank being threaded, a spring under compression between the casing and said magnet and the shoulder of said pole-piece, means permitting movement of said magnet and the pole-piece axially of the latter, a' nut on the threaded end of said shank for adjusting said polepiece and magnet, and a pointer connected with said`nut adapted to coperate with a graduated scale on the back of said casing to indicate the adjustment.

AUGUSTUS ROSENBERG. Witnesses:

GEORGE ERNEST MNTERN, BERTRAM BECK. 

